Momentum (Edexcel GCSE Physics)

Higher Tier Only

Figure 10 shows a small steel ball held at a height, h, above the ground.

Figure 10

The ball is released and allowed to fall to the ground.

The height h is 1.4 m.

Calculate the time, t, for the ball to reach the ground.

Use the equation

g = 10 m/s²

t = ............................................................. s

Higher Tier Only

Two students use the arrangement shown in Figure 10.

They use a stopwatch to time the ball falling through the height of 1.4 m.

The students repeat the measurement many times, but their average value for t is different from the calculated value.

i) Suggest a reason why the students’ value for t is different from the calculated value.

[1]

ii) Suggest one improvement the students could make to their procedure so that their value for t is closer to the calculated value.

[1]

Higher Tier Only

Figure 11a shows a box falling towards a hard floor.

The box hits the floor and crumples a little before it comes to rest as shown in Figure 11b.

The momentum of the box just before it hits the floor is 8.7 kg m/s.

The box comes to rest 0.35 s after it first hits the floor.

i) Calculate the magnitude of the force exerted by the floor on the box.

Use an equation selected from the list of equations at the end of this paper.

force exerted by the floor on the box =.............................. N[2]

ii) State the magnitude and direction of the force exerted by the box on the floor.

magnitude .....................................

direction .....................................

[2]

Higher Tier Only

Figure 12 shows a ball held in a clamp at R, above the ground.

Figure 12

The ball is released from the clamp and falls.

S is 3.8 m below R.

At S the momentum of the ball is 0.40 kg m/s.

Calculate the mass of the ball.

Acceleration due to gravity, g, = 10 m/s²

mass of the ball ....................................................... kg

Higher Tier Only

Complete Figure 1 by writing in the right-hand column the name of the quantity produced by the expression in the left-hand column.

Figure 1

Higher Tier Only

In Figure 2, a man hits a golf ball with a club.

 Figure 2

The ball has a mass of 0.036 kg. The golf club is in contact with the ball for 2.5 × 10^–4 s and the ball leaves the golf club at a speed of 40 m/s. 

(i) Calculate the momentum of the ball as it leaves the golf club to 2 significant figures.

[2]

(ii) Calculate the average resultant force acting on the ball, while it is in contact with the golf club, to 2 significant figures.

[2]

Higher Tier Only

Figure 1 shows a hammer just before it hits a nail into some wood.

Figure 3

The mass of the hammer is 400 g.

When it hits the nail, the hammer is travelling downwards with a velocity of 6.3 m/s.

Calculate the momentum of the hammer.

Higher Tier Only

The hammer comes to rest very soon after it hits the nail.

It takes 0.050 s for the hammer to become stationary.

Calculate the amount of force that causes this to happen.

Higher Tier Only

A person ice skating in Figure 1 throws a 0.20 kg tennis ball with a velocity of 30 m/s.

Figure 1

(i) State the equation linking momentum, mass and velocity.

[1]

(ii) Calculate the initial momentum of the snowball.

[2]

Higher Tier Only

The skater is moving forward when they throw the tennis ball.

This causes their speed to decrease.

Explain why this happens.

Higher Tier Only

The skater has a mass of 65 kg and they have an initial speed of 3.2 m/s.

Calculate their momentum after they have thrown the ball.

Ignore friction.

Higher Tier Only

The skater wears soft knee pads that compress easily.

Explain how the pads protect their knees when they fall on the ice.

Higher Tier Only

Some cars have a pedestrian airbag for safety, as shown in Figure 1.

Figure 1

If a pedestrian is hit and lands on the front of the car, the airbag inflates.

Use ideas about momentum to explain how this airbag can reduce injuries to pedestrians.

Higher Tier Only

In a crash test a car drives through a thin wall.

The momentum of the car before the crash is 27 500 kg m/s. 

An average force with a magnitude of 50 kN acts on the car in the opposite direction to the car's motion over 0.30 s.

Calculate the final momentum of the car after it passes through the wall. 

Higher Tier Only

Car X is travelling down a road to the right at 15 m/s and has a mass of 500 kg.

Car Y is approaching car X from behind at 22 m/s.

The total momentum of the system is 29 500 N s.

Calculate the mass of car Y.

Higher Tier Only

The driver of car Y is on their phone and they crash into the back of car X.

After the collision, both cars stick together and travel forward at the same speed. 

Calculate the combined speed of the cars.

Give your answer to 2 significant figures.

Higher Tier Only

A man is at a carnival playing a game to win a teddy bear.

He has to shoot pellets from a toy rifle at some cans filled with sand, as shown in Figure 1.

Figure 1

He fires a pellet of mass 0.020 kg at the tins. The pellet moves at a velocity of 152 m/s. 

(i) State the equation linking momentum, mass and velocity.

[1]

(ii) Calculate the momentum of the pellet to 2 significant figures.

[2]

Higher Tier Only

The pellet becomes embedded in can 1, as shown in Figure 2.

Figure 2

The mass of can 1 is 0.15 kg. The pellet and can 1 move away together.  

Calculate the velocity of the pellet and can as they move together to 2 significant figures.

Higher Tier Only

The man fires another identical pellet at the same speed at another can identical to can 1.

This time, however, the pellet bounces off with a velocity of −30 m/s.

Calculate the velocity of the can.

Higher Tier Only

The man misses and hits the table on which the cans rest.

Using the concept of inertia, explain why the table does not move as fast as the cans moved when hit.

Higher Tier Only

Figure 1 is a diagram showing a rocket that is sent into space to try and change the path of a small asteroid.

Figure 12

i) The rocket has a mass of 5.5 × 10⁵ kg and is travelling to the right at 14 km/s.

Which of these is a correct calculation of the momentum of the rocket in kg m/s?

ii) The asteroid has a momentum of 7.5 × 10¹⁰ kg m/s and a mass of 8.0 × 10⁶ kg.

Calculate the speed of the asteroid.

 speed of the asteroid = ..................................... m/s[2]

Higher Tier Only

A student investigates the effect of a crumple zone on the force exerted during a collision.

The student has one trolley with a spring at the front and another trolley without a spring.

Figure 13

After a trolley is released, it accelerates down a slope and bounces off a rigid wall.

The speed of a trolley can be measured just before a collision with the wall and just after a collision with the wall.

The silver foils are connected to a millisecond timer.

The silver foils make contact with each other during the collision, so the time they are in contact can be read from the millisecond timer.

Explain how the student could investigate the effect of a crumple zone on the average force exerted during the collision. Your explanation should include:

• how to determine the force (you may wish to refer to an equation from the list of equations at the end of this paper)

• how the effect of crumple zones may be shown in the investigation

• precautions that may be necessary to achieve accurate results

Higher Tier Only

Newton’s third law, when applied to the collision of the rocket and the asteroid as shown in Figure 12, can be stated as follows:

The force exerted by the rocket on the asteroid is equal and opposite to the force exerted by the asteroid on the rocket.

Explain how this statement links to the conservation of momentum in the collision.

Higher Tier Only

Car A has a mass of 600 kg and is travelling at at 30 miles per hour (miles/hour) to the right.

Car B is behind car A and is travelling at 40 miles/hour to the right.

The total momentum of the system is 58 000 kg miles/hour.

Calculate the mass of car B in kg.

Give your answer to 2 significant figures.

Higher Tier Only

The driver of car B is on their phone and they crash into the back of car A.

After the collision, both cars stick together and travel forward at the same speed. 

Calculate the combined speed of the cars, giving the unit. 

Give your answer to 2 significant figures.

Higher Tier Only

Show that kinetic energy is not conserved in this collision.

Higher Tier Only

The collision occurs in 0.55 s.

Calculate the force experienced by car A to the appropriate number of significant figures.

Higher Tier Only

Modern cars all feature crumple zones, which are designed to buckle and break in the event of a crash, as shown in Figure 1.

Figure 1

Derive the equation from the equations  and , where  is force,  is change in momentum,  is time,  is acceleration,  is change in velocity and  is mass.

Higher Tier Only

Using the equation relating force and momentum given in part (a), explain how the crumple zone of the car reduces the risk of injury in a crash.

Higher Tier Only

Using the equation relating force and momentum given in part (a), explain why driving at a lower velocity is generally safer. 

Higher Tier Only

State whether it is safer for the passenger to crash into a wall or a parked vehicle. Explain your answer.